[MISched] Use right boundary when trying latency heuristics

[wangpc-pp]

We may do bottom-up or bidirectional scheduling but previously we
assume we are doing top-down scheduling, which may cause some issues.

[mshockwave]

I suppose this doesn't cause a crash, do you have any example that shows inferior scheduling, which potentially can be a test case?

[mshockwave]

I suppose this doesn't cause a crash, do you have any example that shows inferior scheduling, which potentially can be a test case?

do you by any chance have a test?

[wangpc-pp]

I suppose this doesn't cause a crash, do you have any example that shows inferior scheduling, which potentially can be a test case?

do you by any chance have a test?

Not yet. Actually I did this change not because I met some problems. I did find a problem when handling clustering/fusion in post-ra scheduling, which should be fixed by #116584. Then I just checked other heuristics to see if there may be some other issues, and I found this one. I don't know if I can write a test, the problen here and the fix are clear (we should use the right boundary for different directions).

[michaelmaitland]

LGTM. This is what GenericScheduler does in tryCandidate for tryLatency, so I think it makes sense to take it too.